Spool adapted for gripping a roll of print media

Abstract

A spool, such as supply for a wide-format printer, is provided. The spool comprises a spindle for slidingly receiving an outer shaft, which is typically the core of a roll of print media. A first resiliently deformable gripping ring is circumferentially mounted about the spindle, and a compression mechanism is provided for axially compressing the gripping ring. The axial compression causes radial expansion of the gripping ring, thereby urging the gripping ring into gripping engagement with the outer shaft received on the spindle.

1. A spool for a printer, said spool comprising:
 a spindle for slidingly receiving an outer shaft, said spindle having first and second ends; and 
 a first resiliently deformable gripping ring circumferentially mounted about a first end of said spindle; 
 a second resiliently deformable gripping ring circumferentially mounted about an opposite second end of said spindle; and 
 a compression mechanism for axially compressing said first and second gripping rings simultaneously, said compression mechanism comprising:
 a thrust end-plate releasably engageable with said first end of said spindle; 
 a first abutment surface, positioned towards said first end of said spindle for providing a reaction against said thrust end-plate, said first gripping ring being mounted between said thrust end-plate and said first abutment surface such that, upon thrusting engagement of said thrust end-plate with said spindle, said first gripping ring is axially compressed against said first abutment surface; 
 an inner shaft telescopically engaged in said spindle, said inner shaft having first and second ends corresponding to said first and seconds ends of said spindle; 
 at least one lug projecting radially outwards from said inner shaft, said at least one lug being longitudinally slidingly engaged in a complementary longitudinal slot in said spindle; and 
 a second abutment surface positioned at a second end of said spindle for providing a reaction against said at least one lug, said second gripping ring being mounted between said at least one lug and said second abutment surface such that, upon telescopic expansion of said inner shaft relative to said spindle, said second gripping ring is axially compressed against said second abutment surface by said at least one lug, 
 a reaction end-plate fixed to said end of said inner shaft, 
 a roll of print media received about said spindle, said roll of print media being mounted between and engaged with said thrust end-plate and said reation end-plate; 
 
 
       wherein one end of said roll of print media is urged against said reation end-plate by said thrust end-plate thrusting against an opposite end of said roll of print media, thereby causing said telescopic expansion, 
       and wherein said axial compression causes radial expansion of said gripping rings, thereby urging said gripping rings into gripping engagement with said outer shaft received on said spindle. 
     
     
       2. The spool of  claim 1 , wherein said roll of print media has a cardboard core engaged with said thrust end-plate and said reaction end-plate. 
     
     
       3. The spool of  claim 2 , wherein said gripping rings are formed from a frictional material for frictional gripping engagement with said core. 
     
     
       4. The spool of  claim 1 , wherein said first abutment surface is a surface of a collar positioned towards said first end of said spindle. 
     
     
       5. The spool of  claim 1 , wherein said first end of said spindle is threaded and said thrust end-plate is threadedly engagable therewith. 
     
     
       6. The spool of  claim 1  further comprising a first washer positioned between said first gripping ring and said thrust-end-plate, wherein said washer distributes evenly a compression force from said thrust end-plate onto said first gripping ring. 
     
     
       7. The spool of  claim 1 , wherein said second abutment surface is formed on a circumferential lip at said second end of said spindle. 
     
     
       8. The spool of  claim 1  comprising a pair of diametrically opposed lugs, each projecting radially outwards from said inner shaft, and each being longitudinally slidingly engaged in the respective complementary longitudinal slot in said spindle. 
     
     
       9. The spool of  claim 1  further comprising a second washer positioned between said second gripping ring and said at least one lug, wherein said second washer distributes evenly a compression force from said at least one lug onto said second gripping ring. 
     
     
       10. The spool of  claim 1 , wherein said longitudinal sliding is telescopic expansion of said inner shaft relative to said spindle. 
     
     
       11. The spool of  claim 1 , wherein said reaction end-plate comprises a connector arm for operatively connecting said spool to a motor. 
     
     
       12. The spool of  claim 1 , which is take-up spool or a supply spool for a printer. 
     
     
       13. A wide format printer comprising:
 a printhead; and 
 a feed mechanism for feeding a web of print media past said printhead, said feed mechanism comprising:
 a supply spool; 
 a take-up spool; and 
 a take-up motor operatively connected to said take-up spool, wherein said supply spool and/or said take-up spool is a spool according to  claim 1 .